Field Bulletin · Atmosphere

Pressure & Barometers

The invisible weight of air — from Torricelli's tube to weather forecasting. Visualize atmospheric layers, explore 30 instruments and experiments, and convert pressure units.

Hero · Live Atmosphere

Atmospheric Layers

Earth's atmosphere is a column ~100 km tall but with 99% of its mass below 30 km. Slide through the column to see pressure halve roughly every 5.6 km, temperature reverse direction at each layer boundary, and density fall exponentially.

Altitude0 km
LayerTroposphere
Pressure1013.25 hPa
Temperature15.0 °C
Density1.225 kg/m³
Section 02 · Timeline

From Aristotle to MEMS

Milestones from 350 BC (Aristotle: "nature abhors a vacuum") to 2020 (MEMS pressure sensors at sub-cent prices).

Section 03 · Playground

Hands-on Instruments

Convert between eight common pressure units, watch pressure drop exponentially with altitude, and forecast tomorrow's weather from a barometric trend.